B Philips

Glucose in bronchial aspirates increases the risk of respiratory MRSA in intubated patients

Background: The risk of nosocomial infection is increased in critically ill patients by stress hyperglycaemia. Glucose is not normally detectable in airway secretions but appears as blood glucose levels exceed 6.7–9.7 mmol/l. We hypothesise that the presence of glucose in airway secretions in these patients predisposes to respiratory infection. Methods: An association between glucose in bronchial aspirates and nosocomial respiratory infection was examined in 98 critically ill patients. Patients were included if they were expected to require ventilation for more than 48 hours. Bronchial aspirates were analysed for glucose and sent twice weekly for microbiological analysis and whenever an infection was suspected. Results: Glucose was detected in bronchial aspirates of 58 of the 98 patients. These patients were more likely to have pathogenic bacteria than patients without glucose detected in bronchial aspirates (relative risk 2.4 (95% CI 1.5 to 3.8)). Patients with glucose were much more likely to have methicillin resistant Staphylococcus aureus (MRSA) than those without glucose in bronchial aspirates (relative risk 2.1 (95% CI 1.2 to 3.8)). Patients who became colonised or infected with MRSA had more infiltrates on their chest radiograph (p<0.001), an increased C reactive protein level (p<0.05), and a longer stay in the intensive care unit (p<0.01). Length of stay did not determine which patients acquired MRSA. Conclusion: The results imply a relationship between the presence of glucose in the airway and a risk of colonisation or infection with pathogenic bacteria including MRSA.

Effect of hyperglycaemia on glucose concentration of human nasal secretions.

Glucose is not detectable in airways secretions of normoglycaemic volunteers, but is present at 1-9 mmol x l(-1) in airways secretions from people with hyperglycaemia. These observations suggest the existence of a blood glucose threshold at which glucose appears in airways secretions, similar to that seen in renal and salivary epithelia. In the present study we determined the blood glucose threshold at which glucose appears in nasal secretions. Blood glucose concentrations were raised in healthy human volunteers by 20% dextrose intravenous infusion or 75 g oral glucose load. Nasal glucose concentrations were measured using modified glucose oxidase sticks as blood glucose concentrations were raised. Glucose appeared rapidly in nasal secretions once blood glucose was clamped at approx. 12 mmol x l(-1) ( n =6). On removal of the clamp, nasal glucose fell to baseline levels in parallel with blood glucose concentrations. An airway glucose threshold of 6.7-9.7 mmol x l(-1) was identified ( n =12). In six subjects with normal glucose tolerance, blood glucose concentrations rose above the airways threshold and nasal glucose became detectable following an oral glucose load. The presence of an airway glucose threshold suggests that active glucose transport by airway epithelial cells normally maintains low glucose concentrations in airways secretions. Blood glucose exceeds the airway threshold after a glucose load even in people with normal glucose tolerance, so it is likely that people with diabetes or hyperglycaemia spend a significant proportion of each day with glucose in their airways secretions.

Idiopathic pulmonary fibrosis associated with pulmonary vein thrombosis: a case report.

BackgroundPulmonary vein thrombosis represents a potentially fatal disease. This syndrome may clinically mimic pulmonary embolism but has a different investigation strategy and prognosis. Pulmonary vein thrombosis is difficult to diagnose clinically and usually requires a combination of conventionally used diagnostic modalities.Case PresentationThe authors report a case of a 78-year-old previously healthy female presenting with collapse and shortness of breath. Serum biochemistry revealed acute kidney injury, positive D-dimmers and increased C reactive protein. Chest radiography demonstrated volume loss in the right lung. The patient was started on antibiotics and also therapeutic doses of low molecular weight heparin. The working diagnosis included community acquired pneumonia & pulmonary embolism. A computed tomography pulmonary angiogram was performed to confirm the clinical suspicions of pulmonary embolism. This demonstrated a thrombus in the pulmonary vein, with associated fibrosis and volume loss of the right lower lobe. A subsequent thrombophilia screen revealed a positive lupus anticoagulant antibody and rheumatoid factor and also decreased anti thrombin III and protein C levels. The urine protein/creatinine ratio was found to be 553 mg/mmol.ConclusionThe diagnosis of this patient was therefore of idiopathic pulmonary fibrosis associated with pulmonary vein thrombosis. Whether or not the pulmonary vein thrombosis was a primary cause of the fibrosis or a consequence of it was unclear. There are few data on the management of pulmonary vein thrombosis, but anticoagulation, antibiotics, and, in cases of large pulmonary vein thrombosis, thrombectomy or pulmonary resection have been used.

Paper reports overview: Mortality and morbidity prediction and reduction in the high risk patient

The high-risk patient is a much talked about entity in intensive care circles, but identification of these patients still consumes an abundance of research material. The search continues for that elusive symptom, sign or investigation which has a high sensitivity and specificity. Several of the paper reports over the last couple of months have focused on ways to predict mortality in those patients considered to be high risk. Cole et al looked at heart rate recovery following maximum treadmill stress testing in patients referred for this investigation and therefore presumably presenting with cardiac symptoms and signs. They found that this relatively simple and non-invasive investigation predicted a worse outcome if the heart rate failed to decline rapidly after exercise. Mortality at 6 years was 19% compared to 5% in those patients with a normal heart rate recovery. Perhaps this investigation may help us perioperatively identify those at high risk of cardiac events.